Control system for stand-by electrical generator

ABSTRACT

A generator structure is provided for generating an AC power for a load. The generator structure includes a generator connectable to a load and an engine operatively connected to the generator for driving the same. A generator controller is operatively connected to the engine for controlling operation thereof and operatively connected to a generator for controlling the AC power generated thereby. A communications link connects the generator control to a network.

FIELD OF THE INVENTION

This invention relates generally to engine driven, electricalgenerators, and in particular, to a control system for controllingoperation of the engine and the electrical generator driven therewith.

BACKGROUND AND SUMMARY OF THE INVENTION

Electrical generators are used in a wide variety of applications. As isconventional, electrical generators utilize a single driving enginecoupled to a generator or alternator through a common shaft. Uponactuation of the engine, the crankshaft rotates the common shaft so asto drive the alternator which, in turn, generates electrical power.

Typically, an individual electrical generator operates in either astand-by mode or a parallel mode. In the stand-by mode, the electricalpower provided by a utility is monitored such that if the commercialelectrical power from the utility fails, the engine of the electricalgenerator is automatically started causing the alternator to generateelectrical power. When the electrical power generated by the alternatorreaches a predetermined voltage and frequency desired by the customer, atransfer switch transfers the load imposed by the customer from thecommercial power lines to the electrical generator.

Alternatively, in the parallel mode, the electrical generator supplieselectrical power in parallel with the utility grid. As such, theelectrical power generated by the electrical generator must besynchronized with the commercial electrical power supplied by theutility. Typically, multiple items such as governors, voltage regulatorsand the like are required to synchronize the electrical power generatedby the electrical generator with the commercial electrical powersupplied by the utility. This additional equipment is provided inseparate cabinet units from the electrical generator itself, which addssignificantly to the cost of the electrical generator.

Therefore, it is a primary object and feature of the present inventionto provide an electrical generator incorporating a control system whichcontrols operation of the electrical generator in a stand-by mode or aparallel mode.

It is a further object and feature of the present invention to providean electrical generator which has the ability to supply electrical powerto a load independent of the utility grid, or which may supplyelectrical power in parallel with the utility grid.

It is a still further object and feature of the present invention toprovide an electrical generator which is simple to operate and lessexpensive to manufacture than prior electrical generators.

In accordance with the present invention, a control system is providedfor controlling operation of an engine driven, electrical generator. Theelectrical generator generates AC power and AC voltage for a load. TheAC power has a magnitude and a power factor and the AC voltage has amagnitude and a frequency. The control system includes a generatorcontrol operatively connected to the engine for controlling operationthereof and operatively connected to the generator for controlling theAC power generated thereby. A communications link operatively connectsthe generator control to a network.

A user interface is operatively connected to the network. The userinterface allows the user to communicate with the generator control soas set predetermined operating parameters of the engine and thegenerator.

The control system may include a transfer switch having a first inputconnectable to a utility source for providing AC power, a second inputoperatively connected to the generator, and an output connectable to theload. The transfer switch is selectively movable between a firstposition connecting the utility source to the load and a second positionconnecting the generator to a load. The transfer switch is alsooperatively connected to the generator control such that the generatorcontrol controls movement of the transfer switch between the first andsecond positions.

It is contemplated to interconnect the load to a utility source whichprovides AC power having a magnitude and a power factor and AC voltagehaving a magnitude and a frequency. The control system includes asynchronizer for determining the magnitude and frequency of the ACvoltage of the utility source and a magnitude and frequency of the ACvoltage generated by the generator. The synchronizer is operativelyconnected to the generator control. The generator control varies themagnitude and frequency of the AC voltage generated by the generator tomatch the magnitude and frequency of the AC voltage provided by theutility source. A switch is operatively connected to the generatorcontrol and is movable between a first closed position forinterconnecting the generator and the load and a second open position.The generator control moves the switch to the closed position inresponse to the magnitude and frequency of the AC voltage generated bythe generator being generally equal to the magnitude and frequency ofthe AC voltage provided by the utility source.

The generator control may include a digital governor connectable to theengine for controlling the engine speed of the engine. The digitalgovernor includes a throttle valve movable between a first openedposition where the engine speed is at maximum and a second closedposition where the engine speed is at minimum. The generator control mayalso include a volt-ampere-reactive (VAR) control for varying the powerfactor of the AC power generated by the generator to the predeterminedlevel. In addition, the generator control includes a voltage regulatorfor controlling the magnitude of the AC voltage generated by thegenerator. An alarm system is connectable to the engine for monitoringvarious engine parameters. The alarm system communicates with thegenerator control and generates an alarm signal in response to apredetermined condition on the engine.

In accordance with a further aspect of the present invention, agenerator structure is provided for generating AC power for a load. Thegenerator structure includes a generator connectable to a load. Thegenerator generates AC power having a magnitude and a power factor andan AC voltage having a magnitude and a frequency. An engine isoperatively connected to the generator for driving the generator. Theengine has an adjustable engine speed. A generator control isoperatively connected to the engine for controlling operation thereofand is operatively connected to the generator for controlling AC powergenerated thereby. A communications link operatively connects thegenerator control to a network.

The generator structure may include a transfer switch having a firstinput connectable to a utility source for providing AC power, a secondinput operatively connected to the generator and an output connectableto the load. The transfer switch is selectively movable between a firstposition for connecting the utility source to the load and a secondposition for connecting the generator to the load. The transfer switchis operatively connected to the generator control such that thegenerator control controls movement of the transfer switch between firstand second positions in response to AC power supplied by the utilitysource.

It is contemplated that the load be a utility source which provides ACpower having a magnitude and a power factor and an AC voltage havingmagnitude and a frequency. The generator control includes a synchronizerfor monitoring the magnitude and frequency of the AC voltage provided bythe utility source and a magnitude and frequency of the AC voltagegenerated by the generator. The generator control varies the magnitudeand frequency of the AC voltage generated by the generator to match themagnitude and frequency of the AC voltage of the utility source. Thegenerator control may also include a volt-ampere-reactive (VAR) controlfor varying the power factor of the AC power generated by the generator.

A switch may be operatively connected to the generator control and bemovable between a first closed position wherein the generator isconnected to the utility source and a second open position. Thegenerator control moves the switch to the closed position in response tothe magnitude and frequency of the AC voltage generated by the generatorbeing generally equal to the magnitude and frequency of the AC voltageprovided by the utility source. The generator control includes a digitalgovernor connected to the engine for controlling the engine speed of theengine. The digital governor includes a throttle valve which is movablebetween a first open position wherein the engine speed is at a maximumand a second closed position wherein the engine speed is at a minimum. Agenerator control includes a voltage regulator for regulating themagnitude of the AC voltage generated by the generator.

In accordance with a still further aspect of the present invention, amethod is provided for providing AC power to a load. The method includesthe steps of setting various operating parameters for a generatorstructure and transmitting the same to the generator structure over anetwork. AC power and AC voltage are generated with the generatorstructure in response to the various operating parameters set. The ACpower has a magnitude and a power factor and the AC voltage has amagnitude and a frequency.

It is contemplated that the load be a utility source which provides ACpower having a magnitude and a power factor and AC voltage having amagnitude and a frequency. The method includes the additional step ofmonitoring the magnitude and frequency of the AC voltage provided by theutility source and the magnitude and frequency of the AC voltagegenerated by the generator structure. The magnitude and frequency of theAC voltage generated by the generator structure is varied so as to matchthe magnitude and frequency of the AC voltage provided by the utilitysource. The generator structure and the utility source areinterconnected in response to the magnitude and frequency of the ACvoltage generated by the generator structure be generally equal to themagnitude and frequency of the AC voltage provided by the utilitysource.

In addition, the power factor of the AC power generated by the generatorstructure may be varied to a predetermined level and the AC voltagegenerated by the generator structure may be adjusted to a user selectedmagnitude.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings furnished herewith illustrate a preferred construction ofthe present invention in which the above advantages and features areclearly disclosed as well as others which will be readily understoodfrom the following description of the illustrated embodiment.

In the drawings:

FIG. 1 is a schematic view of a network system for controlling andmanaging the distribution of electrical power;

FIG. 2 is a schematic view of a first embodiment of a power generationsystem;

FIG. 3 is a schematic view of a second embodiment of a power generationsystem;

FIG. 4a is a schematic view of a generator structure for generatingelectrical power for the power generation system of FIG. 3;

FIG. 4b is a schematic view of the generator structure of FIG. 4a forthe power generation system of FIG. 2;

FIG. 5 is a display screen for monitoring the supply and distribution ofelectrical power provided by the power generation systems of FIGS. 1 and2;

FIG. 6 is a generator settings display screen for allowing the user toprovide the generator settings for the generator structure of FIG. 4;

FIG. 7 is a command settings display screen for controlling the startingand stopping of the generator structure of FIG. 4;

FIG. 8 is a holiday settings display screen for allowing a user tospecify days on which the generator structure of FIG. 4 is not operated;

FIG. 9 is a system setting display screen for allowing the user tospecify the settings of the power generation system of FIGS. 2-3; and

FIG. 10 is a clock programming screen for allowing a user to program aday and a time for use with the screens of FIGS. 5-9.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to FIG. 1, a network control system for controlling andmonitoring a plurality of power generation systems is generallygenerated by the reference numeral 10. Each of the power generationsystems is generally designated by the reference numeral 12. Each powergeneration system includes system controller 14 operatively connected toa plurality of generator panels 16 by serial communications link 18.Each generator panel 16 is operatively connected to a correspondinggenerator 20a and 20b, as hereinafter described.

As best seen in FIGS. 4a-4b, generator panel 16 is operatively connectedan engine 22 and a corresponding generator 20a or 20b. It can beappreciated that the following description of generator panel 16operatively connected to generator 20a will be understood to describe asecond generator panel 16 operatively connected to generator 20b, as iffully described herein. Engine 22 receives fuel such as natural gas orliquid propane vapor through an intake. The fuel provided to engine 22is compressed and ignited within the cylinders thereof so as to generatereciprocating motion of the pistons of engine 22. The reciprocatingmotion of the pistons of engine 22 is converted to rotary motion by acrankshaft. The crankshaft is operatively coupled to generator 20athrough shaft 28 such that as the crankshaft is rotated by operation ofengine 22, shaft 28 drives generator 20a which, in turn, converts themechanical energy by engine 22 to electrical power on output 31 ofgenerator 20a for transmission and distribution.

Digital governor 26 is operatively connected to throttle 24 whichcontrols the volume of intake air to engine 22. As is known, digitalgovernor 26 protects engine 22 from overspeed conditions and maintainsengine 22 at a desired engine speed which, in turn, causes generator 20ato generate a desired electrical power at a desired frequency. Digitalgovernor 26 controls the engine speed of engine 22 by regulating theposition of throttle 24, and hence, the amount of fuel and air providedto the combustion chamber of engine 22. As is known, throttle 24 ismovable between a wide-open position wherein engine 22 runs at fullpower and a closed position wherein engine 22 runs at minimum power.Generator control 42 controls operation of digital governor 26, andhence, throttle 24, as hereinafter described.

As is conventional, generator 20a generates AC voltage having amagnitude and a frequency and AC current having a magnitude and afrequency. In alternating current power transmission and distribution,the cosine of the phase angle (θ) between the AC voltage and the ACcurrent is known as the power factor. The AC power generated bygenerator 20a may be calculated in according to the expression:P=I×V×Cos θ

-   -   wherein P is the AC power; I is the root means square of the AC        current; and V is the root means square of the AC voltage.

The magnitude of the AC output voltage of generator 20a is monitored byvoltage regulator 30. As is conventional, generator 20a includes anarmature winding or exciter which controls the magnitude of the ACoutput voltage of generator 20a. Voltage regulator 30 acts to increaseor decrease the excitation of the exciter of generator 20a to the degreeneeded to maintain the magnitude of the AC output voltage at a desiredvalue.

It is contemplated to operatively connect engine 22 and generator 20a toan alarm system 32. Alarm system 32 monitors various operatingconditions of engine 22 and generator 20a and provides a warning if anyof the operating conditions fall outside normal operating levels. Inaddition, alarm system 32 is operatively connected to generator control42 such that generator control 42 may shut down generator 20a inresponse to certain, predetermined alarm conditions on engine 22 and/orgenerator 20a so as to prevent damage to power generation system 12.

Referring to FIGS. 2 and 4b, it is contemplated to connect generators20a and 20b to corresponding loads 34 and 36, respectively, throughcorresponding transfer switches 38. Each transfer switch 38 isolates theelectrical power supplied by a utility on supply line 40 from theelectrical power supplied at outputs 31 of corresponding generators 20aand 20b. Electrical power supplied on supply line 40 is monitored suchthat if the electrical power from the utility fails, engines 22 arestarted by generator controls 42, FIG. 4b, in a conventional manner.With engines 22 of power generation systems 12 started, generators 20aand 20b generate electrical power, as heretofore described. When theelectrical power generated by generators 20a and 20b reaches themagnitude and frequency desired by the user, generator control 42through transfer switch control 33 causes transfer switches 38 totransfer loads 34 and 36 from supply line 40 to corresponding outputs 31of generators 20a and 20b, respectively. In response to restoration ofelectrical power on supply line 40 by the utility, generator controls 42through transfer switch controls 33 cause transfer switches 38 totransfer loads 34 and 36 from outputs 31 of generators 20a and 20b,respectively, to supply line 40. Thereafter, engines 22 are stopped bycorresponding generator controls 42. By stopping engines 22, generators20a and 20b no longer generate electrical power.

Alternatively, referring to FIGS. 3 and 4a, in the event of a poweroutage, generators 20a and 20b may be put in parallel with each other inorder to supply electrical power to load 74. Generators 20a and 20b areput in parallel with each other by connecting outputs 31 of generators20a and 20b to supply line 40. However, prior to connecting outputs 31of generators 20a and 20b to supply line 40, it is necessary to matchthe magnitude of the AC output voltage of generator 20a with themagnitude of the AC output voltage of generator 20b. In addition, theoutputs of generators 20a and 20b must be synchronized. In order tosynchronize the outputs of generators 20a and 20b, the phase sequencesand the frequencies of the outputs of generators 20a and 20b must beidentical. Once synchronized, generator control 42 through transferswitch control 33 causes transfer switches 44a and 44b to close suchthat outputs 31 of generators 20a and 20b, respectively, are coupled tosupply line 40. Thereafter, supply line 40 is connected to load 74, ashereinafter described.

It is also contemplated to put generators 20a and 20b in parallel withthe utility by connecting outputs 31 of generators 20a and 20b to theutility. In order to put generators 20a and 20b in parallel with theutility, it is necessary to match the magnitude of the AC outputvoltages of generators 20a and 20b with the magnitude of the AC voltageof the utility. In addition, the outputs of generators 20a and 20b mustbe synchronized with the utility. In order to synchronize the outputs ofgenerators 20a and 20b with the utility, the phase sequences and thefrequencies of the outputs of generators 20a and 20b must be identicalin phase and frequency with the utility.

Referring back to FIGS. 4a and 4b, by way of example, voltage matchingis accomplished by voltage regulators 30 of generator panels 16. Eachvoltage regulator 30 is supplied with the magnitude of the AC voltageprovided by the utility, as hereinafter described, and thereafter,raises or lowers the AC voltage provided by corresponding generators 20aor 20b to precisely match the magnitude of the AC voltage provided bythe utility under the control of corresponding generator controls 42 ofgenerator panels 16. As such, it is contemplated to operatively connectgenerator controls 42 of generator panels 16 to supply line 40 tomonitor the utility. Synchronization is achieved by increasing ordecreasing the engine speed, as heretofore described, such that phasesequence and the frequency of the AC outputs of generators 20a and 20bare identical to the phase and frequency supplied by the utility.Synchronizers 35 monitor the AC power provided by the utility andprovide such information to corresponding generator controls 42. Oncesynchronization is achieved, transfer switches 44a and 44b are closed bygenerator controls 42 through transfer switch controls 33 such thatoutputs 31 of generators 20a and 20b, respectively, are coupled tosupply line 40. Thereafter, supply line 40 is connected to the utility,as hereinafter described.

When generators 20a and 20b are connected in parallel with the utility,the AC output voltages of generators 20a and 20b cannot be varied byexcitation of corresponding exciters of generators 20a and 20b.Excitation of exciters of generators 20a and 20b controls the powerfactors of the electrical power supplied by generators 20a and 20b tothe utility. As such, the excitation of exciters of generators 20a and20b when generators 20a and 20b are connected in parallel with theutility is known as volt-ampere-reactance (VAR) control, block 50.

Further, when generators 20a and 20b are connected in parallel with theutility, the opening and closing of throttles 24 by digital governors 26does not change the engine speeds of corresponding engines 22. Theopening and closing of throttles 24 increases the AC power supplied tothe utility by generators 20a and 20b. As such, the opening and closingof throttles 34 24 when generators 20a and 20b are connected in parallelwith the utility is known as power control, block 52.

Generator controls 42 of the generator panels 16 are operativelyconnected to serial communications link 18 by communication interfaces56. In the preferred embodiment, each communication interface 56 is aRS485. Referring to FIGS. 2 and 3, serial communications link 18 allowssystem controller 14 to communicate with generator controls 42 ofgenerator panels 16. System controller 14 includes a microcontroller anda visual display. The microcontroller executes a software program whichis displayed on the visual display of system controller 14. The softwareprogram allows a user to monitor the electrical power supplied by theutility; to monitor various operating conditions of the engines andgenerators of the power generation systems 12; and to control variousoperating parameters of power generation systems 12.

Referring to FIG. 3, in a first embodiment, system controller 14 isoperatively connected by line 58 to the utility to monitor the utilityand to measure the voltage and current provided by the utility. Inaddition, system controller 14 is operatively connected by line 59 tosupply line 40 to monitor the electrical power supplied by generators20a and 20b. System controller 14 is also operatively connected toswitches 61 and 63 by lines 65 and 67 in order to control the openingand closing of switches 61 and 63, for reasons hereinafter described. Inan alternate embodiment, FIG. 2, system controller 14 is connected byline 69 to the utility to monitor the utility and to measure the voltageand current provided by the utility.

The magnitudes of the voltage and current provided by the utility aredisplayed on display screen 60, FIG. 5. Display screen 60 includesvoltage display 62 for displaying the magnitude of the rms voltageprovided by the utility and current display 64 for displaying themagnitude of the rms current provided by the utility. System controller14 calculates the power supplied by the utility and power factor of thepower supplied and displays the same on display screen 60 at powerdisplay 66 and power factor display 68, respectively.

Display screen 60 also includes utility icon 70 representing theutility, load icon 72 representing load 74, and generator icons 76 and78 representing corresponding generators 20a and 20b, respectively.Generator power displays 80 and 82 are positioned adjacent correspondinggenerator icons 76 and 78, respectively, to display the power and powerfactor of the outputs of generators 20a and 20b. In addition, the totalpower provided by generators 20a and 20b is displayed by total powerdisplay 84. Display screen 60 also includes a time display 86 fordisplaying the date and time, as well as, power connections havingswitch icons 88a-d therein which represent the states of switches 61,63, 44a and 44b, respectively, of FIG. 3.

System controller 14 further includes generator settings screen 90, FIG.6, for allowing a user to input a plurality of settings for generators20a and 20b. Generator setting screen 90 includes number-of-generatorsinput 92 for allowing a user to input the number of generators connectedto communications link 18. In addition, generator setting screen 90includes inputs for identifying the generator (either generator 20a orgenerator 20b) for which the settings on the generator settings screenpertain 94; the maximum kilowatts produced by the identified generator96; the recommended minimum kilowatts for efficient operation of theidentified generator 98; the maximum power which may be produced by theidentified generator in volt-ampere-reactance 100; the priority ofoperation of the identified generator as compared to the othergenerators of the power generation system 102; and a slave address forthe generator control 42 of generator panel 16 for the identifiedgenerator 104. Generator settings scroll bar 105 is provided forallowing a user to scroll through the settings for each generator.

Referring to FIG. 7, system controller 14 further includes a commandsettings screen generally designated by the reference numeral 106.Command settings screen 106 allows a user to input various parametersfor starting and stopping generators 20a and 20b. Command settingsscreen 106 includes inputs for identifying: a command (by number) foroperation of the generators (either generator 20a and generator 20b)108; a mode the user desires the generators to operate during aprescribed time period 110; the maximum kilowatts to be produced by thegenerators or consumed from the utility during the prescribed timeperiod depending on the mode selected by the user 112; and a userselected limit for the power factor of the electrical power produced bythe generators or consumed from the utility during the prescribed timeperiod depending on the mode selected by the user 114.

Command setting screen 106 also includes inputs for identifying theprescribed time period for which a user desires the generators tooperate under the identified command. These inputs include a month 116and a day 118 for starting the identified generator and a month 120 anda day 122 for stopping the generators. Inputs are also provided for anhour 124 and a minute 126 for starting the generators on each day forwhich the generators are intended to operate and an hour 128 and aminute 130 for stopping the generators on each day for which thegenerators are intended to operate. Inputs are also provided foridentifying specific days of the week and holidays 132a-h during theprescribed time period for which the generators are intended not tooperate. Command scroll bar 131 is provided for allowing the user toscroll through each command.

Referring to FIG. 8, system controller 14 further includes a holidayscreen generally designated by the reference numeral 134. Holiday screen134 includes inputs for a user: to identify holidays (by number) onwhich generators 20a and 20b will not be operational 135; and to specifya month 136 and a day 138 for each holiday identified. Holiday scrollbar 137 is provided for allowing the user to scroll through each holidayidentified.

As best seen in FIG. 9, system controller 14 includes a system settingsscreen generally designated by the reference numeral 142. Systemsettings screen 142 includes inputs for a user: to specify if a passwordis needed 144a to connect system controller 14 to network 172, forreasons hereinafter described, and if a password is needed 144b tointerconnect system controller 14 to serial communications link 18; tospecify a password 146 which must be entered by a user at input 146 togain access to screens of FIGS. 6-10; to specify a current transformerratio which steps down the current provided by utility so as to allowsuch current to be measured by the ammeter of system controller 14; tospecify a voltage scaling factor to calibrate the volt meter whichmeasures the voltage provided by the utility 150; and to specify asystem voltage 152 to be generated by power generation system 12(typically, the utility voltage).

Referring to FIG. 10, a clock-programming screen is generally designatedby the reference numeral 154. Clock programming screen 154 includes ascrollable calendar display 156 for displaying a calendar to a user. Inaddition, the clock-programming screen 154 includes inputs for allowinga user to specify the month 158, the day of the month 160, the year 162,the weekday 164, the hour 166 and the minute 168. The day and timeinputted on clock-programming screen 154 are displayed by time display86 on display screen 60.

In operation, for each power generation system 12, generator panels 16and system controller 14 are connected to a common serial communicationslink 18. Initially, a user inputs a plurality of settings for generators20a and 20b on generator settings screen 90 and the various parametersfor starting and stopping generators 20a and 20b on command settingsscreen 106 of system controller 14, as heretofore described. Inaddition, the user enters the inputs heretofore described on holidayscreen 134, system settings screen 142, and clock programming screen 154of system controller 14. Thereafter, in order to gain access to thevarious screens of system controller 14, the user is prompted to enterthe password provided at input 146 of system settings screen 142. Afterobtaining access to the various screens of system controller 14, theuser may monitor power generation system 12 and/or may vary the inputs,as heretofore described.

With respect to power generation systems 12 of FIGS. 1-2 and 4b, systemcontroller 14 monitors the electrical power supplied to supply line 40by the utility. The magnitude of the rms voltage provided by the utilityand the magnitude of the rms current provided by the utility aredisplayed on display screen 60, FIG. 5. In addition, the power suppliedby the utility and power factor of the power supplied are displayed ondisplay screen 60. Further, display screen 60 displays the date andtime, as well as, the power connections of power generation system 12.

If the electrical power from the utility fails, generator controls 42 ofgenerator panels 16 start engines 22 such that generators 20a and 20bgenerate electrical power, as heretofore described. When the electricalpower generated by generators 20a and 20b reaches the magnitude andfrequency desired by the user, transfer switches 38 transfer loads 34and 36 from supply line 40 to corresponding outputs 31 of generators 20aand 20b, respectively. The power and power factor of the outputs ofgenerators 20a and 20b, as well as, the total power provided bygenerators 20a and 20b to loads 34 and 36, respectively, are displayedon display screen 60. Display screen 60 also updates the powerconnections of power generation system 12.

In response to restoration of electrical power on supply line 40 by theutility, generator controls 42 of generator panels 16 cause transfersswitches 38 to transfer loads 34 and 36 from outputs 31 of generators20a and 20b, respectively, to the utility connected to supply line 40.Thereafter, generator controls 42 stop corresponding engines 22 suchthat generators 20a and 20b no longer generate electrical power.

Alternatively, generators 20a and 20b may be placed in parallel with autility by connecting outputs 31 of generators 20a and 20b to theutility through supply line 40. As heretofore described, in order to putgenerators 20a and 20b in parallel with the utility, it is necessary tomatch the magnitudes of the AC output voltages of generators 20a and 20bwith the magnitude of the AC voltage of the utility. In addition, theoutputs of generators 20a and 20b must be synchronized with the utilitysuch that the phase sequences and the frequencies of the outputs ofgenerators 20a and 20b are identical in phase and frequency with theutility.

Once the outputs of generators 20a and 20b are synchronized with theutility and the magnitudes of the AC output voltages of generators 20aand 20b match of the AC voltage of the utility, generator controls 42 ofgenerator powers panels 16 cause transfer switches 38 to close such thatloads 34 and 36 are operatively connected to the utility through supplyline 40 and to outputs 31 of generators 20a and 20b, respectively. TheAC power and power factor provided by generators 20a and 20b, as wellas, the total power provided by generators 20a and 20b, respectively,are displayed on display screen 60. Display screen 60 also updates thepower connections of power generation system 12. It can be appreciatedthat generator controls 42 of generator panels 16 control the powerfactors of the electrical power supplied by corresponding generators 20aand 20b and the AC power supplied by generators 20a and 20b, asheretofore described, in accordance with the inputs provided by a useron command settings screen 106.

Referring to the embodiment of FIGS. 3 and 4a in the event of a poweroutage, system controller 14 advises each of generator controls 42 ofgenerator panels 16 accordingly. Generator controls 42 of generatorpanels 16 start engines 22 such that generators 20a and 20b generateelectrical power, as heretofore described. When the electrical powergenerated by generators 20a and 20b reaches the magnitude and frequencydesired by the user, transfer switches 44a and 44b close so as toconnect supply line 40 to corresponding outputs 31 of generators 20a and20b, respectively. Thereafter, system controller 14 opens switch 61 andcloses switch 63 in order to connect supply line to load 74, and tohence, transfer load 74 from the utility to generators 20a and 20b. Thepower and power factor provided by generators 20a and 20b, as well as,the total power provided by generators 20a and 20b to load 74, aredisplayed on display screen 60. Display screen 60 also updates the powerconnections of power generation system 12.

In response to restoration of electrical power by the utility, systemcontroller 14 advises generator controls 42 of generator panels 16accordingly. Thereafter, system controller 14 closes switch 61 and opensswitch 63 in order to connect the utility to load 74. In addition,generator controls 42 of generator panels 16 open transfer switches 44aand 44b so as to disconnect the outputs 31 of generators 20a and 20b,respectively, from supply line 40. Generator controls 42 stopcorresponding engines 22 such that generators 20a and 20b no longergenerate electrical power, or alternatively, system controller 14returns to operating generators 20a and 20b, as provided by a user oncommand setting screen 106 Display screen 60 updates the informationdisplayed thereon accordingly.

Alternatively, generators 20a and 20b may be placed in parallel with theutility by connecting outputs 31 of generators 20a and 20b to theutility through supply line 40. As heretofore described, in order to putgenerators 20a and 20b in parallel with the utility, it is necessary tomatch the magnitudes of the AC output voltages of generators 20a and 20bwith the magnitude of the AC voltage of the utility. In addition, theoutputs of generators 20a and 20b must be synchronized with the utilitysuch that the phase sequences and the frequencies of the outputs ofgenerators 20a and 20b are identical in phase and frequency with theutility.

Once the outputs of generators 20a and 20b are synchronized with theutility and the magnitudes of the AC output voltages of generators 20aand 20b match of the AC voltage of the utility, transfer switches 44aand 44b close such that outputs 31 of generators 20a and 20b areconnected to supply line 74 40. Thereafter, system controller 14 closesswitch 63 in order to connect supply line 40 to the utility and to load74. The power and power factor provided by generators 20a and 20b, aswell as, the total power provided by generators 20a and 20b to load 74,are displayed on display screen 60. Display screen 60 also updates thepower connections of power generation system 12.

It is contemplated that system controller 14 incorporate a load sheddingfeature such that if the electrical power from the utility fails and ifthe plurality of generators in power generation system 12 are inadequateto provide sufficient electrical power to support load 74, systemcontroller 14 may disconnect a portion of load 74 from supply line 40. Acircuit breaker with a shunt trip is provided in series with portions ofload 74. If the electrical power from the utility fails, systemcontroller 14 trips the circuit breaker and removes a correspondingportion of load 74 from the system. It is contemplated that multipleload shedding relays be provided and the system controller 14 only shedsuch portion of load 74 as necessary to allow the generators of powergeneration system 12 to provide adequate electrical power to the load.By way of example, if one or more of the plurality of electricalgenerators of power generation system 12 are off line, additionalportions of the load may be shed in order to for the generators inoperation to provide adequate electrical power to load 74.

Referring back to FIG. 1, it is contemplated that network system 10include a network controller 170 which is operatively connected to acommunication network 172 such as a telephone network, a computernetwork, the internet, or a combination for communication thereon.Network controller 170 includes a microprocessor and one or more visualdisplays. It is further contemplated to interconnect systems controller14 to the communication network 172, as heretofore described. It iscontemplated that the microcontroller of network controller 172 170execute a software program so as to allow a user to access each systemcontroller 14 and selectively display the screens, FIGS. 5-10 of theselected system controller 14 on the visual display of the networkcontroller 170. As such, the network system 10 allows for a single userto monitor several power generation systems 12 from a single locale andto control operation of these power generation systems 12 in theheretofore described. Consequently, a user is able to view the currentoperating conditions of each of the power generation systems 12, as wellas, configure system controllers 14 from the remote locale. In addition,the user can obtain detailed information from individual generators 20aand 20b from the remote locale.

Various modes of carrying out the invention are contemplated as beingwithin the scope of the following claims particularly pointing out anddistinctly claiming the subject matter which is regarded as theinvention.

1. A control system for controlling operation of an engine-driven,electrical generator which generates AC power and AC voltage having amagnitude and a frequency for a load, the load being operativelyconnected to a utility source which provides AC power having a magnitudeand power factor and AC voltage having a magnitude and a frequencythereto, and the engine having an adjustable engine speed, comprising: agenerator control operatively connected to the engine for controllingoperation thereof and operatively connected to the generator forcontrolling the AC power generated thereby; a synchronizer operativelyconnected to a the generator control, the synchronizer monitoring themagnitude and frequency of the AC voltage of the utility source and themagnitude and frequency of the AC voltage generated by the generator;and a communications link for operatively connecting the generatorcontrol to a network; wherein the generator control adjusts themagnitude of the AC voltage generated by the generator and adjusts theengine speed of the engine to vary the frequency of the AC voltagegenerated by the generator such that the magnitude and frequency of theAC voltage generated by the generation matches the magnitude andfrequency of the AC voltage of the utility source.
 2. The control systemof claim 1 further comprising a user interface operatively connected tothe network, the user interface allowing a user to communicate with thegenerator control so as to set predetermined operating parameters of theengine and the generator.
 3. The control system of claim 1 furthercomprising a transfer switch having a first input connectable to theutility source for providing AC power, a second input operativelyconnected to the generator, and an output connectable to an alternateload, the transfer switch is selectively movable between a firstposition connecting the utility source to the alternate load and asecond position connecting the generator to the alternate load.
 4. Thecontrol system of claim 3 wherein the transfer switch is operativelyconnected to the generator control such that the generator controlcontrols movement of the transfer switch between the first and secondpositions.
 5. The control system of claim 1 further comprising a switchoperatively connected to the generator control and being movable betweena first closed position for interconnecting the generator and the loadand a second open position, the generator control moving the switch tothe closed position in response to the magnitude and frequency of the ACvoltage generated by the generator being generally equal to themagnitude and frequency of the AC voltage provided by the utilitysource.
 6. The control system of claim 1 wherein the generator controlincludes a digital governor connectable to the engine for controllingthe engine speed of the engine.
 7. The control system of claim 6 whereinthe digital governor includes a throttle valve, the throttle valvemovable between a first open position wherein the engine generatesmaximum AC power and a second closed position wherein the enginegenerates minimum AC power.
 8. The control system of claim 1 wherein thegenerator control includes a voltage regulator for controlling themagnitude of the AC voltage generated by the generator.
 9. The controlsystem of claim 1 further comprising an alarm system connectable to theengine for monitoring various engine parameters, the alarm systemcommunicating with the generator control and generating an alarm signalin response to a predetermined condition on the engine.
 10. A generatorstructure for generating AC power for a load, the load including autility source which provides AC power having a magnitude and powerfactor and AC voltage having a magnitude and frequency, comprising: agenerator connectable to the load, the generator generating AC powerhaving a magnitude and a power factor and AC voltage having a magnitudeand a frequency; an engine operatively connected to the generator fordriving the generator, the engine having an adjustable engine speed; agenerator control operatively connected to the engine for controllingoperation thereof and operatively connected to the generator forcontrolling the AC power generated thereby, the generator controlincluding a synchronizer for monitoring the magnitude and frequency ofthe AC voltage provided by the utility source and the magnitude andfrequency of the AC voltage generated by the generator wherein thegenerator control adjusts the magnitude of the AC voltage generated bythe generator and adjusts the engine speed of the engine to vary thefrequency of the AC voltage generated by the generator such that themagnitude and frequency of the AC voltage generated by the generator themagnitude and frequency of the AC voltage of the utility source; and acommunications link for operatively connecting the generator control toa network.
 11. The generator structure of claim 10 further comprising atransfer switch having a first input connectable to a utility source forproviding AC power, a second input operatively connected to thegenerator, and an output connectable to an alternate load, the transferswitch selectively movable between a first position for connecting theutility source to the alternate load and a second position forconnecting the generator to the alternate load.
 12. The generatorstructure of claim 11 wherein the transfer switch is operativelyconnected to the generator control such that the generator controlcontrols movement of the transfer switch between the first and secondpositions in response to the AC power supplied by the utility source.13. The generator structure of claim 10 further comprising a switchoperatively connected to the generator control and being movable betweena first closed position wherein the generator is connected to theutility source and a second open position, the generator control movingthe switch to the closed position in response to the magnitude andfrequency of the AC voltage generated by the generator being generallyequal to the magnitude and frequency of the AC voltage provided by theutility source.
 14. The generator structure of claim 10 wherein thegenerator control includes a digital governor connectable to the enginefor controlling the engine speed of the engine.
 15. The generatorstructure of claim 14 wherein the digital governor includes a throttlevalve, the throttle valve movable between a first open position whereinthe engine generates maximum AC power and second closed position whereinthe engine generates minimum AC power.
 16. The generator structure ofclaim 10 wherein the generator control includes a voltage regulator forregulating the magnitude of the AC voltage generated by the generator.17. A control system for controlling operation of an engine-driven,electrical generator which generates AC power and AC voltage having amagnitude and a frequency for a load, the load being operativelyconnected to a utility source which provides AC power having a magnitudeand power factor and AC voltage having a magnitude and a frequencythereto, and the engine having an adjustable engine speed, comprising: agenerator control operatively connected to the engine for controllingoperation thereof and operatively connected to the generator forcontrolling the AC power generated thereby, the generator controlincluding a volt-ampere-reactive (VAR) control for varying the powerfactor of the AC power generated by the generator to a predeterminedvalue; a synchronizer operatively connected to a the generator control,the synchronizer monitoring the magnitude and frequency of the ACvoltage of the utility source and the magnitude and frequency of the ACvoltage generated by the generator; and a communications link foroperatively connecting the generator control to a network; wherein thegenerator control varies the magnitude and frequency of the AC voltagegenerated by the generator to match the magnitude and frequency of theAC voltage of the utility source.
 18. A generator structure forgenerating AC power for a load, the load including a utility sourcewhich provides AC power having a magnitude and power factor and ACvoltage having a magnitude and frequency, comprising: a generatorconnectable to the load, the generator generating AC power having amagnitude and a power factor and AC voltage having a magnitude and afrequency; an engine operatively connected to the generator for drivingthe generator, the engine having an adjustable engine speed; a generatorcontrol operatively connected to the engine for controlling operationthereof and operatively connected to the generator for controlling theAC power generated thereby, the generator control including avolt-ampere-reactive (VAR) control for varying the power factor of theAC power generated by the generator; the generator control including asynchronizer for monitoring the magnitude and frequency of the ACvoltage provided by the utility source and the magnitude and frequencyof the AC voltage generated by the generator such that the generatorcontrol the magnitude and frequency of the AC voltage generated by thegenerator the magnitude and frequency of the AC voltage of the utilitysource; and a communications link for operatively connecting thegenerator control to a network.
 19. A method of providing AC power to aload, the load including a utility source which provides AC power havinga magnitude and a power factor and an AC voltage having a magnitudes anda frequency, comprising the steps of: setting various operatingparameters for a generator structure and transmitting the same to thegenerator structure over a network; and generating AC power and ACvoltage with a generator structure in response to the various operatingparameters set, the AC power having a magnitude and a power factor andthe AC voltage having a magnitude and a frequency; monitoring themagnitude and the frequency of the AC voltage provided by the utilitysource and the magnitude and the frequency of the AC voltage generatedby the generator structure; varying the magnitude and the frequency ofthe AC voltage generated by the generator structure to match themagnitude and the frequency of the AC voltage provided by the utilitysource, and interconnecting the generator structure to the utilitysource in response to the magnitude and the frequency of the AC voltagegenerated by the generator structure being generally equal to themagnitude and the frequency of the AC voltage provided by the utilitysource.
 20. The method of claim 19 comprising the additional step ofvarying the power factor of the AC power generated by the generatorstructure to a predetermined value.
 21. The method of claim 19comprising the additional step of adjusting the magnitude of the ACvoltage generated by the generator structure to a user selectedmagnitude.